Building an optics and photonics research ecosystem in South Korea: Collaborative innovation between academia and industry

Photonics research is a rapidly growing ﬁ eld that has found applications in various aspects of our lives, ranging from communication to medical imaging 1 – 5 . Collaborative innovation between academia and industry has been a driving force behind the signi ﬁ cant advances in photonics research in South Korea. In this special issue, we present cutting-edge research in photonics, highlighting the importance of collaboration between academia and industry (Fig. 1). This issue covers a wide range of topics in photonics including biomedical applications 6 – 8 , imaging 9 – 11 , micro light emitting diodes ( μ LED) 12 , quantum dot emitters 13 , deformable displays 14 , thin-ﬂ at optics 15,16 , radiative cooling 17 , and 2D optical devices 18 – 20 . Additionally, we introduce upcoming disruptive photonic applications with periodically arranged structures and their integration with conventional optics 15,21 . By uniting researchers from academia and industry, we hope to foster a culture of collaboration and innovation in photonics research in South Korea, paving the way for practical applications in various ﬁ elds. This special issue can serve as a reference for the current and future research directions of photonics in South Korea.


E D I T O R I A L O p e n A c c e s s
Building an optics and photonics research ecosystem in South Korea: Collaborative innovation between academia and industry Younghwan Yang 1 , Trevon Badloe 1,2 , Duheon Song 3,7 , Seongjin Park 4 and Junsuk Rho 1,5,6 ✉ Photonics research is a rapidly growing field that has found applications in various aspects of our lives, ranging from communication to medical imaging [1][2][3][4][5] .Collaborative innovation between academia and industry has been a driving force behind the significant advances in photonics research in South Korea.In this special issue, we present cutting-edge research in photonics, highlighting the importance of collaboration between academia and industry (Fig. 1).This issue covers a wide range of topics in photonics including biomedical applications [6][7][8] , imaging [9][10][11] , micro light emitting diodes (μLED) 12 , quantum dot emitters 13 , deformable displays 14 , thin-flat optics 15,16 , radiative cooling 17 , and 2D optical devices [18][19][20] .Additionally, we introduce upcoming disruptive photonic applications with periodically arranged structures and their integration with conventional optics 15,21 .By uniting researchers from academia and industry, we hope to foster a culture of collaboration and innovation in photonics research in South Korea, paving the way for practical applications in various fields.This special issue can serve as a reference for the current and future research directions of photonics in South Korea.
Recent advancements in biophotonics have led to the development of novel materials and techniques for various biomedical applications.One such material is a upconversion materials, which have shown promise in photochemical tissue bonding 6 .In addition, a computational strategy based on deep neural networks has been developed to reconstruct high-density super-resolution images from a few raw images, thereby improving temporal and spatial resolution in various biological and medical modalities 7 .Furthermore, microscopy-based frameworks that identify pathogens from single to few cells have been proposed as a potential solution to the long turnaround time of routine microbial identifications 8 .These innovative approaches hold great potential for advancing biophotonics and improving medical technologies.
Similarly, Korean academia has made continuous advancements in scanning technology to address current limitations and challenges.These developments aim to capture fast and intricate mechanical dynamics in realtime, enabling direct time-domain imaging of displacements and mechanical motions.For example, a line-scan time-of-flight (TOF) camera has been developed using electro-optic sampling with a frequency comb, which simultaneously measures TOF changes of more than 1,000 spatial coordinates with sub-nanometer axial resolution and a field-of-view of over several millimeters 10 .This unique combination of performance enhancements enables fast and precise imaging of both complex structures and dynamics in 3D devices and mechanical resonators.Additionally, a novel referencefree 3D polarization-sensitive computational imaging technique, termed polarization-sensitive intensity diffraction tomography, has been developed 11 .It enables the reconstruction of the 3D anisotropy distribution of both weakly and multiple scattering specimens from multiple intensity-only measurements.These advancements in scanning technology open up new possibilities for investigating the nature of anisotropic materials and studying the full-field structural and dynamic behaviors of micro-and nano-scale devices.
In the field of sensing, a novel sensing strategy using a single μLED-embedded photoactivated gas sensor has been proposed 12 .By utilizing time-variant illumination equipped with a deep neural network, the system is able to selectively identify and quantify the concentrations of various target gases with high accuracy.This approach may significantly improve the efficiency of electronic sensing technology in terms of cost, space, and power consumption.Meanwhile, a paradigm-shifting photonic crystal (PhC) phosphor platform has been further improved by increasing the refractive index contrast and planarizing the surface 13 .The upgraded PhC phosphor exhibits unprecedentedly high absorption and emission efficiency, which may further spur the development of structural engineering of phosphor materials.
Furthermore, collaborative innovation between Korean academia and industry has led to significant advancements in practical applications, including metasurfaceintegrated optical components 15 , large-area metaholograms 16 , hollow cavities 21 , and deformable displays 14 .Metasurfaces offer versatile capabilities for controlling electromagnetic waves and ongoing research aims to integrate them with standard optical components for commercialization 15 .One-step nanoprinting with ZrO 2 particle-embedded resin enalbes scalable production of metaholograms in the ultraviolet 16 .Hollow cavities have unique optical characteristics and can be tailored to specific spectra and applications, making them promising platforms for optoelectronic devices 21 .Deformable displays have already been commercialized, and efforts are being made to develop 3D free-form displays for use in tactile sensation, artificial skin, and on-skin or implantable displays 14 .Industrial commercialization of these technologies presents several challenges and prospects.
Research in Korean industries is increasingly being geared towards environmental considerations.One notable area of research is radiative cooling 17 , a passive energy-free cooling technology.The review on radiative cooling in this issue explores the fundamentals of thermodynamic heat transfer that motivate radiative cooling, and discusses various photonic structures inspired by nature and their associated design procedures.The integration of photonic structures with new functionalities has also enhanced the efficiency of radiative cooling technologies, enabling applications such as reducing cooling loads in vehicles, increasing the power generation of solar cells, and personal thermal regulation.The article concludes with a discussion on emerging issues and potential solutions for the future of radiative cooling.
Moreover, Korean researchers have focused on the application of 2D Dirac materials in optoelectronics, harnessing the collective oscillations of massless particles to create atomically thin devices with exceptional optoelectronic functions 18 .Graphene and 3D topological insulators have shown promising results in terms of midinfrared and terahertz radiation confinement, enabling advancements in bio-molecular sensors, photodetectors, and laser-driven light sources.Additionally, an electrical and spectral method of resolving chiral exceptional points in a non-Hermitian gated graphene metasurface has been proposed, leading to the observation of enhanced asymmetric polarization conversion 19 .The authors anticipate that electrically controllable non-Hermitian metasurface platforms can serve as an interesting framework for the investigation of rich non-Hermitian polarization dynamics around chiral exceptional points.
Another area of interest in Korea is the design and manufacturing of ultra-thin graphene optics, such as planar diffractive lenses (PDL) that can be patterned on ultra-thin and flexible substrates and conformally attached to arbitrarily shaped surfaces, making them ideal for compact and lightweight optical systems for various applications 20 .The use of direct laser writing of laserinduced-graphene is actively being applied to the patterning of PDLs, offering high design flexibility, low process complexity, and a chemical-free process with reasonable investment cost.In-depth studies on photonmaterial interactions with different laser parameters have enabled the production of exemplary laser-written 1D and 2D PDL structures using various base materials.The combination of ultra-thin PDLs with conventional bulk refractive or reflective optical elements has the potential to leverage the advantages of each optical element and enable the realization of hybrid PDLs for various industries, including micro-electronics surface inspection, biomedical applications, outer space exploration, and extended reality industries.
In the field of ophthalmology, the development of multifocal and extended depth of focus intraocular lenses (IOLs) has revolutionized vision correction 9 .These IOLs, embedding micro-thin geometric phase (GP) lens layers, surpassing conventional diffractive IOLs in terms of multifocality while avoiding the need for additional surface patterns.By adjusting the number of stacked GP layers and their thickness, the GP IOLs can achieve various focal points and light splitting ratios, providing enhanced vision capabilities.
As mentioned earlier, South Korea has fostered extensive industry-academia collaboration research, with a particularly focus on the next-generation display and nanophotonic devices.One notable example is the POSCO-POSTECH-RIST convergence research center for flat optics and metaphotonics, which plays a pivotal role in bridging the gap between science and technology by promoting the academia-industry collaboration model in South Korea.The center has already proposed massive production process of large-area metalenses at the visible spectrum 22 and organized integrated metasurfaces for commercialization 15 .In addition to POSCO, other domestic companies in South Korea are increasingly demonstrating interest in academia-industry collaboration and startup initiatives, embracing open innovation.Through such collaborations, these companies are seeking technological innovation in their existing businesses and exploring new ventures.This growing trend in South Korea signifies the importance of fostering partnerships and promoting open innovation to drive both technological advancements and the discovery of new business opportunities.
In conclusion, the research presented in this special issue highlights the crucial role of collaboration between academia and industry in driving the advancements of photonics research.The innovative approaches showcased here have significant potential for advancing biophotonics, exploring the characteristics of anisotropic materials, and investigating the structural and dynamic behaviors of micro-and nano-scale devices.Furthermore, the practical industrybased research presented in this issue, such as metasurfaceintegrated optical components 15 , hollow cavities 21 , and deformable displays 14 , holds great promise for commercialization.We are optimistic that this special issue will inspire further collaboration and innovation in photonics research in South Korea, ultimately leading to more real-life applications and technological advancements in various fields.Additionally, the emphasis on environmental sustainability, as exemplified by research on radiative cooling 17 , demonstrates a commitment to environmentallyfriendly and energy-efficient technologies.

Fig. 1
Fig. 1 Collaboration in Korea academia and industry.Collaborative innovation has been carried out in diverse fields including biophotonics, imaging, emitters, deformable displays, radiative cooling, and thin-flat optics within the Korean industry and research community